Generally, castings leak on pressurization due to defects/porosities. The porosities in the castings are caused by internal shrinkages or gas cavity, oxide films and inclusions etc.
To prevent leaks in the casting during pressurization, vacuum impregnation of the casting is carried out. Vacuum impregnation is the process of sealing the porosity in castings. Specifically, an impregnation material, or the impregnant, also called sealant or resin is introduced into the porosity within the wall thickness of the casting using vacuum. The liquid sealant that penetrates into the porosities is subsequently cured by heating at elevated temperature.
A fully automated system having a basket loaded with castings is generally used to impregnate castings. During the process of impregnation using the existing basket, the half-filled baskets with castings cannot be used without the basket being balanced and the components being fixtured tightly. Further, the castings in the baskets get damaged due to collision to each other during the process of impregnation if they are not restricted from movement within the basket. Further, the baskets must be suitable for handling multiple castings of different shapes and sizes therein to ensure that the components fit correctly in the basket as well as also can be fixed in some way to prevent them from colliding against each other. Moreover the baskets also need to be universal for the fully automated system so that there is optimum space utilization within the basket in a balanced condition when loaded, fully or partially.
Accordingly, there exists a need to provide a system for impregnation of castings that overcomes the above mentioned drawbacks of the prior art.